The Facebook-owned service attempted to claim the right to sell user photos to advertising partners without notification or compensation, but has now announced that its terms will revert back to their original 2010 wording.

"It became clear that we failed to fulfil what I consider one of our most important responsibilities - to communicate our intentions clearly. I am sorry for that, and I am focused on making it right," said Instagram founder and CEO Kevin Systrom.

"Going forward, rather than obtain permission from you to introduce possible advertising products we have not yet developed, we are going to take the time to complete our plans, and then come back to our users and explain how we would like for our advertising business to work."

Scores of Instagram users, including celebrities and organisations such as National Geographic, removed their accounts in response to the firm's initial announcement.

However, Systrom has reiterated that his company never had any intention of selling or claiming ownership of users' images.

"I want to be really clear: Instagram has no intention of selling your photos, and we never did. We don't own your photos - you do," he said.

Instagram's updated terms of service and privacy policy will come into effect on January 19.